De-glitch switching converting circuit and controller thereof
A de-glitch switching converting circuit and a controller thereof are provided. In the embodiment of the invention, the circuit can filter noises with high frequency by way of time judgment, so as to avoid the erroneous operation of the controller affecting the stability of the output voltage or the output current. Compared with the method of using low-pass filters with large capacitors to filter noises, highly increasing the cost of the circuit is unnecessary in the embodiment of the invention. The circuit in the embodiment of the invention also has the capability for filtering noises with high amplitudes. In addition, by setting suitable parameters, the circuit in the embodiment of the invention can also avoid affecting the transient response of the circuit while filtering noises.
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This application claims the priority benefit of China application serial no. 201010117549.0, filed on Mar. 2, 2010. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
BACKGROUND OF THE INVENTION1. Field of the Invention
The invention relates to a switching converting circuit and a controller thereof. More particularly, the invention relates to a de-glitch switching converting circuit and a controller thereof.
2. Description of Related Art
For power supplies, switching converting circuits are mainstream products in the current market due to superior properties of high converting efficiency, small size, and low power consumption while no load. However, switching converting circuits have the disadvantages of complex circuit design, large ripples, and large electromagnetic interference (EMI). In the current market, common switching converting circuits mainly have two types of control methods. One is pulse width modulated (PWM), and the other is pulse frequency modulated (PFM). Due to constant frequency in PWM technology, EMI is more easily filtered, and the capability of de-glitch is stronger. However, the disadvantages of switching converting circuits with PWM technology are low converting efficiency and slow transient response while light load. On the contrary, PFM technology has advantages of high converting efficiency and fast transient response. However, EMI is not easily filtered, and the capability of de-glitch is weak in switching converting circuits with PFM technology.
Referring to
In order to reduce noise interference, Richtek Technology Corp. discloses an apparatus and a method for noise sensitivity improvement to a switching system in U.S. Pat. No. 7,023,253.
However, in order to filter noises, the LPF 16 provided in the foregoing patent requires a larger capacitor to achieve the objective of filtering. Hence, it is necessary to increase the area of the die to dispose the capacitor for filtering or increase the pins of the chip to externally connect the capacitor for filtering, such that the cost is increased. In addition, for noises with high amplitudes, the circuit may also erroneously operate such that the stability of the output voltage is still affected.
SUMMARY OF THE INVENTIONIn the related art, by using low-pass filters for reduce noise interference, the cost of the circuit is increased, and the issue of noises with high amplitudes can not be overcome. Accordingly, the embodiment of the invention can avoid the cost of the circuit increasing and filter noises with high amplitudes by way of time judgment. In addition, by setting suitable filtering parameters, the transient response of the circuit may be not affected.
An embodiment of the invention provides a controller of a de-glitch switching converting circuit including a noise filtering unit, an on-time unit, and a driving unit. The noise filtering unit determines whether to output a pulse signal according to a predetermined time length and a condition of which an output voltage of the de-glitch switching converting circuit is lower than a predetermined output voltage. The on-time unit outputs a constant pulse width signal according to the pulse signal. The driving unit controls the de-glitch switching converting circuit according to the constant pulse width signal such that the output voltage is stabilized at the predetermined output voltage.
Another embodiment of the invention provides a de-glitch switching converting circuit including a converting circuit and a controller. The converting circuit transmits an electrical power of a DC input power source to an output end according to at least one control signal, so as to provide a DC output voltage to drive a load. The controller determines whether to output the at least one control signal according to a predetermined time length and a condition of which the DC output voltage of the de-glitch switching converting circuit is lower than a predetermined output voltage, wherein a pulse width of the at least one control signal is constant.
Another embodiment of the invention provides a controller of a de-glitch switching converting circuit including a noise filtering unit, an on-time unit, and a driving unit. The noise filtering unit determines whether to output a pulse signal according to a predetermined time length and a condition of which a load current flowing through a load provided by the de-glitch switching converting circuit is lower than a predetermined output current. The on-time unit outputs a constant pulse width signal according to the pulse signal. The driving unit controls the de-glitch switching converting circuit according to the constant pulse width signal such that the load current is stabilized at the predetermined output current.
Another embodiment of the invention provides a de-glitch switching converting circuit including a converting circuit and a controller. The converting circuit transmits an electrical power of a DC input power source to an output end according to at least one control signal, so as to provide a DC output voltage to drive a load. The controller determines whether to output a pulse signal according to a predetermined time length and a condition of which a load current flowing through a load provided by the de-glitch switching converting circuit is lower than a predetermined output current, wherein a pulse width of the at least one control signal is constant.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. In order to make the features and the advantages of the invention comprehensible, exemplary embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Accordingly, when the level of the feedback signal FB is rapidly and temporarily lower than that of the reference signal Vre1 due to noises, the comparing unit 112 temporarily outputs the comparing signal to the delay unit 120. However, the output time thereof is shorter than the predetermined time length, such that the delay unit 120 does not output the pulse signal PWM. Hence, it may ensure that noises do not affect the operation stability of the switching converting circuit. When the output voltage of the switching converting circuit is lower than the predetermined output voltage, it causes that the feedback signal FB is continuously lower than the reference signal Vre1. At this time, the delay unit 120 outputs the pulse signal PWM such that the on-time unit 135 generates a constant pulse width signal Ton. The driving unit 150 generates at least one control signal Gate according to the constant pulse width signal Ton, such that the switching converting circuit transmits electrical power to the output end to boost the level of the feedback signal FB. In addition, by setting a suitable predetermined time length, the effect of the noise is reduced, and the switching converting circuit has a better transient response.
The noise filtering unit 210 includes a comparing unit 212, an inverter 214, a current source 221, a first switch 222, a second switch 224, a capacitor 226, and a comparator 228. The first switch 222 and the second switch 224 respectively control the charge and the discharge of the capacitor 226. Alternately conducting the first switch 222 and the second switch 224 is better. The comparing unit 212 receives the feedback signal FB and a reference signal Vre1 and generates a comparing signal 213 with a high level to conduct the first switch 222 when the feedback signal FB is lower than the reference signal Vre1. The first switch 222 is coupled to the current source 221 and the capacitor 226 and charges the capacitor 226 by the current of the current source 221 when being conducted. At this time, the inverter 214 inverts the comparing signal 213 to output a signal with a low level to cut off the second switch 224. Accordingly, a voltage drop 225 of the capacitor 226 gradually increases. When the feedback signal FB is higher than the reference signal Vre1, the comparing unit 212 generates the comparing signal 213 with the low level to cut off the first switch 222 to stop charging the capacitor 226. At this time, the inverter 214 inverts the comparing signal 213 to output a signal with the high level to conduct the second switch 224 such that the capacitor 226 discharges. Accordingly, the voltage drop 225 decreases to zero. The comparator 228 compares the voltage drop 225 and a reference voltage Vb and outputs a pulse signal PWM when the voltage drop 225 is higher than the reference voltage Vb.
The rising edge triggering unit 230 is coupled to the noise filtering unit 210 and generates a rising edge detecting signal to trigger the on-time unit 235 to generate a constant pulse width signal Ton when detecting the rising edge of the pulse signal PWM. The driving unit 250 generates a first control signal UG to control the switch of the first switch M1 according to the constant pulse width signal Ton and generates a second control signal LG to control the switch of the second switch M2 according to a current detecting signal CS which represents the size of the current flowing through the second switch M2 and the first control signal UG, such that the current IL of the inductor L can flow through the second switch M2 when the first switch M1 is cut off. The constant pulse width signal Ton is also transmitted to the minimum off-time unit 245. The minimum off-time unit 245 generates a minimum off-time signal Toff having a constant pulse width to the rising edge triggering unit 230 when detecting the falling edge of the constant pulse width signal Ton. During the period in which the rising edge triggering unit 230 receives the minimum off-time signal Toff, the rising edge triggering unit 230 stops detecting the rising edge of the pulse signal PWM to ensure that the energy stored in the inductor L can be released.
The noise filtering unit 310 includes a comparing unit 312, an inverter 314, a first current source 321, a first switch 322, a second current source 323, a second switch 324, a capacitor 326, and a comparator 328. The first switch 322 and the second switch 324 respectively control the charge and the discharge of the capacitor 326.
The rising edge triggering unit 330 generates a rising edge detecting signal to trigger the on-time unit 335 to generate a constant pulse width signal Ton when detecting the rising edge of the pulse signal PWM. The driving unit 350 generates a control signal Gate to conduct the transistor switch M3 according to the constant pulse width signal Ton. The constant pulse width signal Ton is also transmitted to the minimum off-time unit 340. The minimum off-time unit 340 generates a minimum off-time signal Toff having a constant pulse width to the rising edge triggering unit 330 when detecting the falling edge of the constant pulse width signal Ton. During the period in which the rising edge triggering unit 330 receives the minimum off-time signal Toff, the rising edge triggering unit 330 stops detecting the rising edge of the pulse signal PWM to ensure that the energy stored in the inductor L can be released.
It should be noted that, the dotted circles A and B in
Similarly, by adding an AND gate to receive the inverting signal 315 outputted by the inverter 314 and the constant pulse width signal Ton to control the second switch 324, the DC-to-DC buck converting circuit shown
Base on the above, in the embodiment of the invention, the circuit can filter noises with high frequency by way of time judgment, so as to avoid the erroneous operation of the controller affecting the stability of the output voltage or the output current. Compared with the method of using low-pass filters with large capacitors to filter noises, highly increasing the cost of the circuit is unnecessary in the embodiment of the invention, and the circuit in the embodiment of the invention has the capability for filtering noises with high amplitudes. In addition, by setting suitable parameters, the circuit in the embodiment of the invention can also avoid affecting the transient response of the circuit while filtering noises.
As the above description, the invention completely complies with the patentability requirements: novelty, non-obviousness, and utility. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the invention covers modifications, and variations of this invention if they fall within the scope of the following claims and their equivalents.
Claims
1. A controller of a de-glitch switching converting circuit, comprising:
- a noise filtering unit determining whether to output a pulse signal according to a predetermined time length and a condition of which an output voltage of the de-glitch switching converting circuit is lower than a predetermined output voltage;
- an on-time unit outputting a constant pulse width signal according to the pulse signal; and
- a driving unit controlling the de-glitch switching converting circuit according to the constant pulse width signal such that the output voltage is stabilized at the predetermined output voltage,
- wherein the noise filtering unit outputs the pulse signal when the output voltage is continuously lower than the predetermined output voltage for the predetermined time length.
2. The controller of the de-glitch switching converting circuit as claimed in claim 1, wherein the noise filtering unit comprises a comparing unit and a delay unit, the comparing unit outputs a comparing signal when the output voltage is lower than the predetermined output voltage, and the delay unit outputs the pulse signal when the comparing signal continuously exists for the predetermined time length.
3. The controller of the de-glitch switching converting circuit as claimed in claim 1, wherein the delay unit comprises:
- a capacitor;
- a first current source providing a first current to charge the capacitor;
- a first switch controlling the first current to charge the capacitor according to the comparing signal;
- a second switch discharging the capacitor according to the comparing signal or the constant pulse width signal; and
- a comparator comparing a voltage drop across the capacitor and a reference voltage and outputting the pulse signal when the voltage drop across the capacitor is higher the reference voltage.
4. The controller of the de-glitch switching converting circuit as claimed in claim 3, wherein the delay unit further comprises a second current source providing a second current to discharge the capacitor, and the second switch discharges the capacitor by the second current according to the comparing signal, wherein the second current is larger than the first current.
5. The controller of the de-glitch switching converting circuit as claimed in claim 1, wherein the noise filtering unit determines outputs the pulse signal when a accumulating time for which the output voltage is lower than the predetermined output voltage is longer than the predetermined time length during each period.
6. The controller of the de-glitch switching converting circuit as claimed in claim 5, wherein the noise filtering unit comprises a comparing unit and an accumulating delay unit, the comparing unit outputs a comparing signal when the output voltage is lower than the predetermined output voltage, and the accumulating delay unit outputs the pulse signal when the accumulating time for which the comparing signal exists is longer than the predetermined time length.
7. A de-glitch switching converting circuit, comprising:
- a converting circuit transmitting an electrical power of a DC input power source to an output end according to at least one control signal, so as to provide a DC output voltage to drive a load; and
- a controller determining whether to output the at least one control signal according to a predetermined time length and a condition of which the DC output voltage of the de-glitch switching converting circuit is lower than a predetermined output voltage, wherein a pulse width of the at least one control signal is constant,
- wherein the controller comprises a noise filtering unit, and the noise filtering unit outputs the at least one control signal when the DC output voltage is continuously lower than the predetermined output voltage for the predetermined time length.
8. The de-glitch switching converting circuit as claimed in claim 7, wherein the controller comprises a comparing unit and a delay unit, the comparing unit outputs a comparing signal when the DC output voltage is lower than the predetermined output voltage, the delay unit outputs the at least one control signal when an accumulating time for which the comparing signal exists is longer than the predetermined time length during each period.
9. The de-glitch switching converting circuit as claimed in claim 7, wherein the converting circuit is a DC-to-DC buck converting circuit or a DC-to-DC boost converting circuit.
10. A controller of a de-glitch switching converting circuit, comprising:
- a noise filtering unit determining whether to output a pulse signal according to a predetermined time length and a condition of which a load current flowing through a load provided by the de-glitch switching converting circuit is lower than a predetermined output current;
- an on-time unit outputting a constant pulse width signal according to the pulse signal; and
- a driving unit controlling the de-glitch switching converting circuit according to the constant pulse width signal such that the load current is stabilized at the predetermined output current,
- wherein the noise filtering unit outputs the pulse signal when the load current is continuously lower than the predetermined output current for the predetermined time length.
11. The controller of the de-glitch switching converting circuit as claimed in claim 10, wherein the noise filtering unit comprises a comparing unit and a delay unit, the comparing unit outputs a comparing signal when the load current is lower than the predetermined output current, and the delay unit outputs the pulse signal when the comparing signal continuously exists for the predetermined time length.
12. The controller of the de-glitch switching converting circuit as claimed in claim 11, wherein the delay unit comprises:
- a capacitor;
- a first current source providing a first current to charge the capacitor;
- a first switch controlling the first current to charge the capacitor according to the comparing signal;
- a second switch discharging the capacitor according to the comparing signal or the constant pulse width signal; and
- a comparator comparing a voltage drop across the capacitor and a reference voltage and outputting the pulse signal when the voltage drop across the capacitor is higher the reference voltage.
13. The controller of the de-glitch switching converting circuit as claimed in claim 12, wherein the delay unit further comprises a second current source providing a second current to discharge the capacitor, and the second switch discharges the capacitor by the second current according to the comparing signal, wherein the second current is larger than the first current.
14. A de-glitch switching converting circuit, comprising:
- a converting circuit transmitting an electrical power of a DC input power source to an output end to provide a DC output voltage to drive a load; and
- a controller determining whether to output a pulse signal according to a predetermined time length and a condition of which a load current flowing through a load provided by the de-glitch switching converting circuit is lower than a predetermined output current, wherein a pulse width of the at least one control signal is constant,
- wherein the controller comprises a noise filtering unit, and the noise filtering unit outputs the at least one control signal when the load current is continuously lower than the predetermined output current for the predetermined time length.
15. The de-glitch switching converting circuit as claimed in claim 14, wherein the controller comprises a comparing unit and a delay unit, the comparing unit outputs a comparing signal when the load current is lower than the predetermined output current, and the delay unit outputs the at least one control signal when an accumulating time for which the comparing signal exists is longer than the predetermined time length during each period.
16. The de-glitch switching converting circuit as claimed in claim 14, wherein the converting circuit is a DC-to-DC buck converting circuit or a DC-to-DC boost converting circuit.
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Type: Grant
Filed: Oct 18, 2010
Date of Patent: Jul 16, 2013
Patent Publication Number: 20110215780
Assignee: Green Solution Technology Co., Ltd (New Taipei)
Inventors: Li-Min Lee (Taipei County), Chung-Che Yu (Taipei County), Shian-Sung Shiu (Taipei County), Ji-Ming Chen (Wuxi)
Primary Examiner: Rajnikant Patel
Application Number: 12/906,137
International Classification: G05F 1/40 (20060101);